With the worldwide tendency toward a healthier lifestyle, a number of researches have been conducted about the functions of fatty acids in oil or fat. For example, there are reports about the effects of saturated fatty acids or trans unsaturated fatty acids on health (see Non-patent Documents 1 and 2).
Also, conjugated linoleic acid and diacylglycerol have been found to have an anti-obesity effect or the like (see Patent Documents 1 to 5). Further, oils or fats with diacylglycerol having a high content of a specific fatty acid such as an ω-3 fatty acid or linoleic acid are known (see Patent Documents 6 to 8).
In addition, it is known to combine diacylglycerol with a plant sterol, thereby improving the blood cholesterol level or the like (see Patent Documents 9 to 14).
The use of diacylglycerol as a cooking oil is known to have some advantages, such as less occurrence of substantial foaming during frying, and an increase in the improvement of flavor and texture (see Patent Documents 15 and 16). Diacylglycerols have also been proven to be applicable to emulsified products (see Patent Documents 17-19). From these viewpoints, oil or fat compositions of high diacylglycerol content are widely used as edible oils.    Patent Document 1: PCT International Publication Pamphlet No. WO 96/06605    Patent Document 2: PCT International Publication Pamphlet No. WO 98/37873    Patent Document 3: JP-A-04-300826    Patent Document 4: JP-A-10-176181    Patent Document 5: JP-A-2001-64671    Patent Document 6: PCT International Publication Pamphlet No. WO 01/109899    Patent Document 7: PCT International Publication Pamphlet No. WO 02/11552    Patent Document 8: EP-A-0679712    Patent Document 9: PCT International Publication Pamphlet No. WO 99/48378    Patent Document 10: JP-A-2002-34453    Patent Document 11: PCT International Publication Pamphlet No. WO 00/73407    Patent Document 12: JP-A-2000-206100    Patent Document 13: JP-A-2002-171931    Patent Document 14: JP-A-2001-335795    Patent Document 15: JP-A-11-243857    Patent Document 16: JP-A-02-190146    Patent Document 17: JP-B-1915615    Patent Document 18: PCT International Publication Pamphlet No. WO 96/32022    Patent Document 19: JP-A-03-8431    Non-patent Document 1: “The New England Journal of Medicine”, USA, the Massachusetts Medical Society, 340(25), 1933-1940 (1999)    Non-patent Document 2: U.S. FDA, “Questions and Answers about Trans Fat Nutrition Labeling”, [online], Internet <URL: http://www.cfsan.fda.gov/˜dms/qatrans2.html>